Not far outside the town of Saint-Rémy-de-Provence in the south of France, on a rise overlooking a field of sunflowers, stands the Mas de Baraquet. It is the kind of place the French do well, a country manor more understated than grandiose. Its limestone facade, with its simple elegance, bespeaks an ancient patrimony rather than overt richesse. “It’s an 18th-century home,” says Laure Jakobiak, my lissome young guide. “You can identify its era by the high shuttered windows. The 17th century was more austere. In the 18th, people wanted to open the windows more to let in the light.” At the same time, she continues, the height of the windows, the ironwork balcony over the front door, and the triple row of Mediterranean tiles at the edge of its roof identify the house as a noble one, the former home of a titled family, whose ancient portraits adorn the living room walls.

Yet it is the imperfections, rather than the conventions of architecture, that give this place its character. There is a dignity about the chipped stone pillars at its gate, a timelessness to the horse trough worn smooth by centuries of use, a pathos to the stone benches cushioned in deep green moss.

Even so, the property owes its magic to something other than the passage of time, for—its windows and ancient stonework to the contrary—in the 18th century Mas de Baraquet did not exist. Nor was it standing in the 19th century or for almost all of the 20th—at least not in its present state. “This was an old barn,” explains Jakobiak. “The only things that were here were the walls and the foundation.” The noblemen depicted on the salon walls never slept beneath this roof. In the orangerie, where the home’s present owner now takes breakfast, enjoying the morning sun filtering in over the citrus plants, farm animals once were penned. The stone pillars that support a trellis are not really stone, as they first appear, but rather cement, which was not invented until the late 19th century. “We use authentic materials where possible,” my guide notes, “but sometimes we have to substitute something more modern, as long as it doesn’t interfere with the feel of the place.”

Elsewhere in Provence, similar metamorphoses have taken place. Ancient ruins have been transformed into folies, abandoned abbeys have been turned into ancestral manors, and rustic shepherd’s huts have become stylish villas, all bearing that most elusive element: the patina of age. If these homes serve to confuse the line between fantasy and reality, tant mieux, so much the better. “Some of the walls, the fireplaces, the doors, you can’t tell if they’re original or if they’ve been added,” Jakobiak says. “That’s the way it should be.”

These properties are not for everyone. Transforming a barn into an 18th-century showplace such as Mas de Baraquet is costly, and few may be inclined to spend millions of dollars for a residence that appears to have been untouched for centuries, or, as is the case with many of these restorations, whose gardens are so vast and elaborate they can be appreciated only from a belvedere. But then, if all you wish is to build a house, you can hire an architect. To realize the fantasy that is Provence, you must come to Jakobiak’s employer, Bruno Lafourcade.

“What we do is not the kind of thing they teach at the universities,” Lafourcade says later that day, as he wheels his black Porsche 911 Cabriolet past the limestone hills that bear the scars of Roman excavations from two millennia earlier. “At the universities, architects learn how to use computers. They do not learn taste, they do not learn charm, they do not learn culture.” Lafourcade, who appears to be in his late 50s, and his 32-year-old son, Alexandre, do not build with computers. “We build with the images we carry in our heads,” he says. “We must know how the local winds blow, how a tree will protect a home in the summer, and how the mistral will blow off the surrounding hills in winter. Then we must listen to the client as carefully as a doctor making a diagnosis. Do they have dogs? Do they love music? Do they love flowers? You are not merely designing a residence, you are creating a way of life.”Today, however, Lafourcade is coming from a meeting with a prospective client, an American, and he is not happy with what the client has proposed. “Jacuzzis!” he erupts. “Why do these people always want an outdoor hot tub, or a swimming pool, when a reflecting pool is so much nicer?” He shudders, as if envisioning a gaggle of paunchy, Speedo-clad pool-party guests strutting about in front of one of his 18th-century masterpieces. Another American fetish Lafourcade resists is “the fitness.” “Who comes to Provence to lift weights?” he asks. “I tell them, ‘If you insist, I will build you a fitness room, but you will never use it.’ ” Equally unnecessary, he says, is air-conditioning. “You do not need it. All they have to do is open the windows in the morning, close them in the afternoon, and the house will be cool. Sometimes they insist on having these things anyway, and then a year later they tell me, ‘Bruno, you were right.’ ”

Most of the time, though, Lafourcade’s clients accede to his advice. After all, they are working with one of France’s preeminent architects, are they not? He is the very model, one might say, of the good life to which wealthy newcomers to Provence aspire. Lafourcade and his strikingly attractive wife, Dominique, who oversees the landscaping for her husband’s restoration projects, inhabit a baronial estate—Les Confines—of their own design. The garages house a tasteful array of new and vintage automobiles and motorcycles including the 1927 Bugatti he raced at last year’s Tourist Trophy at Le Mans and a 1937 Bugatti coupe that is the color of milk chocolate. His contributions to French culture have earned him the thanks of his countrymen and the title of Chevalier of the Order of Arts and Letters. He is a welcome—and frequent—guest at such renowned temples of gastronomy as Oustau de Beaumanière in nearby Baux. Prestigious American publications, understandably dazzled by his creations, have described him as the finest architect in Provence.

There is just one thing wrong with this picture. Lafourcade is not an architect, nor did he ever study architecture in college. In fact, he never attended college. The man so celebrated for reshaping and elevating the Provence landscape, the son of a well-to-do Renault executive, dropped out of school at age 15 to enter the scrap iron reclamation business. “I always had in my brain an interest and passion for old buildings,” he says. “And I liked working with my hands. The scrap metal business was a nice way to combine these two interests.”

By the mid-1960s, after a three-year stint with the French army in Algeria, Lafourcade had teamed with an elderly mason to try his hand at a business closer to his heart: architectural restoration. “It was a good time to start,” he says. “In the 1960s there were lots of properties in need of restoration, and the old mason taught me a lot. He had excellent taste, and he knew where to find just the right materials.”

Their first project involved a small manor house with a tower, which took nine months to rebuild. “I remember we used a lot of cracked marble in that house,” he recalls. “It took on a kind of classical Grecian look.” It did not take long to sell, and by the end of that first year, the young entrepreneur and his mentor had six more restorations under way. The projects were small, but people soon were taking note of Lafourcade’s handiwork, his sense of authenticity, and his attention to detail. Real estate brokers, eager to market the possibilities represented in a medieval ruin or dilapidated mansion, began referring their clients to him. “At first my clients were all French, then English,” Lafourcade says. “The English have a taste for old things.”

In 1970 his artistry won him the grand prize in France’s National Restoration Competition, and a few years later he was profiled in Le Figaro, one of the country’s largest newspapers. But his vault to international stardom came when a prominent realtor introduced Lafourcade to an American lady, Anne Cox Chambers of Atlanta, who had acquired a property in Provence. Chambers, who was said to be worth $12 billion, was not only wealthy, she also was influential. Soon every millionaire in Atlanta had to have a restored château or villa in Provence. This was fine with Lafourcade, who was more than willing to accommodate them. In recent years, he says, the influx from Atlanta has slowed, but since then Americans have become the most numerous of his clients. “They see Provence differently from the French,” he explains. “For them, it is a far more romantic place than it is for the people who were born here.”

The restored Le Manoir, set amid the ancient limestone quarries of Baux, now houses guests for one of France’s most renowned restaurants, Jean-Andre Charial’s Oustau de Beaumanière. Photograph by Pere Planells.

It was the romantic allure of Provence that drew Manhattanites Donald and Gun Bauchner here. “We’ve been coming to Provence since 1998,” says Mrs. Bauchner, a native of Sweden. “We love it: the countryside, the food, the pace, and the people.”

Her husband, president of the New York–based Perfumers Workshop, which creates and sells fragrances for men and women, concurs. “Provence is unique,” he says. “You can’t be too slick here, like in Saint-Tropez. And you can’t be too formal, like in Paris. It’s more like the British shabby-chic lifestyle.”

Once they decided to buy a home in Provence, their real estate agent led them first to a remote hillside bergerie—a shepherd’s dwelling—in the rugged Luberon region of Provence and then to Lafourcade. “As you can see, the location was fine,” says Mrs. Bauchner, leading the way through her rustic hideaway. “We had a marvelous view of fir trees across the valley, but the main house was in ruins. There were just crude walls and a gate.” She looks around her retreat; with its rough-hewn stone walls, its front porch with bamboo awnings, and its tented anteroom, the house is decidedly eclectic, at once evoking Robinson Crusoe, Marrakech, and an artist’s atelier. “Where we’re standing didn’t even exist,” Mrs. Bauchner says, looking around her living room. “So before we bought it, we had Bruno look at the place to tell us how much it would cost to restore and expand.”

Thus forearmed for the restoration project they faced, the Bauchners purchased the property. There was, as Donald Bauchner recalls, just one problem: Once work began, it became evident that the restoration was going to cost far in excess of the original estimate. This, he decided, was because Lafourcade dealt only with a small number of masons, contractors, roofers, carpenters, and other craftsmen. “I said, ‘Can’t we get estimates from other contractors?’ But Bruno just said, ‘If you can’t work with them, then you can’t work with me.’ ”

Ultimately the restoration project cost the couple two and a half times what they had expected. “But you know what,” Mr. Bauchner says, “it was worth it.” To say the least, the Bauchners’ hillside idyll is one-of-a-kind, with gardens built on three levels and a waterfall splashing over a cave by the pool house. “It’s great fun to sit in the cave behind the waterfall,” says Mrs. Bauchner.

However, they do have one regret: the air-conditioning. “Bruno told me not to bother installing it, but I insisted,” says Mr. Bauchner. “Now I never use it.”

Americans are not the only clients who cling to reminders of their native land, says Dominique Lafourcade the next day, as she strolls the grounds of a castle where a mammoth restoration project is in progress. “Our clients often want to grow flowers or shrubs from their native land,” she notes. “And the British love flowers. But so many of the flowers that grow in England don’t grow here. So for one British client, I created a garden that used different colors of French flowers. When they bloom, they will form a Union Jack.”

This client, she says, pointing to the castle, is from Holland. “He wants to grow tulips in the gardens. But tulips won’t grow here; the mistral is too strong. I will have to think of some other way to give him a little piece of Holland in the middle of Provence.”The fact that Dominique is here suggests that the project is in the late stage of restoration. “I start to work on the gardens once the exterior has been done,” she says, “to provide a unified look.” She points to the castle’s turrets, where geometric patterns in vivid hues adorn the spires. These, she explains, are the colors of the owner’s Bugattis, which are housed in an outbuilding on the other side of the château. Alas, the garage is designed so that those inside can see out, but those outside cannot see in.

The scene at the castle grounds is a welter of activity, with earth movers chugging back and forth, reshaping the contours of the land, and workmen putting the finishing touches on limestone sculptures and the moldings over the windows and doors. Lafourcade patrols the site as though he were a field commander urging on his troops, and then he walks over to join his wife. “Once we have begun, the most important thing on a project is to keep the contractors moving,” he says. “You have to constantly motivate them. If they lose their momentum, everything comes to a halt. An architect creates in his office; we do it on site, where we are constantly reminded of the natural setting, the limitless possibilities.”

Although this château is immense, he says, his goal is the same for it as it would be for a small mas. “We don’t want to lose those little imperfections that give a place its charm,” Lafourcade says. “Above all, we don’t want it to look modern. I saw a Bugatti recently that had been completely redone. It looked brand-new. It was a shame.”

To ensure that he does not commit the error common to other restorers, Lafourcade employs a team of researchers who identify sources of old materials and study bygone architectural patterns and regional differences in style. Then, too, what is authentic in one part of Provence may not be so in another. The tomette tiles of Aix, for instance, will not do for Saint-Rémy, where floors are of limestone or terra-cotta, or for Saint-Tropez, where there would be extensive use of the pebbles called calades. “The magic lies in rebuilding invisibly,” he says, “to maintain the sense of authenticity.”

This philosophy, say the Bauchners, pervades their hillside hideaway. “It still amazes me,” says Donald Bauchner. “I think our house became half again as large in the restoration process, but you can’t tell what is old and what is new.”

This was evident when, shortly after the Bauchners had moved in, a group of real estate professionals came to visit. “They asked as politely as they could, ‘It’s a lovely place, but has it been restored yet?’ ”